Screw implant and system and method for locking a screw in an implant plate

ABSTRACT

A plate system and method comprising a plate and a screw having an integral resilient lock. The screw comprises a head that has a portion that is adapted to be compressible as it is screwed into bone using a tool. After the screw head is received in the plate and the tool is removed therefrom, the screw head decompresses or expands into a locking or receiving area, thereby locking the screw in the plate. The plate is adapted to have at least one or a plurality of detents or lips for cooperating with at least a portion of the screw head to retain the screw in the plate and prevent it from withdrawing therefrom.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/026,405, filed Sep. 13, 2013, which is a continuation-in-part of U.S.patent application Ser. No. 12/612,209, filed Nov. 4, 2009, which issuedas U.S. Pat. No. 8,535,356, to which Applicant claims the benefit of theearlier filing date.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to surgical implants and, more particularly, itrelates to a surgical implant plate and a screw having a screw headhaving at least a portion that is compressible when a tool, such as ascrew driver, engages and compresses the portion of the screw head sothat it can be received in the plate. Thereafter, the screw head canexpand or decompress in order to lock the screw in the plate uponretraction or dismounting of the tool from the screw head.

2. Description of the Related Art

In the past, various types of implant plates and screw lockingmechanisms have been proposed. For example, several surgical implantdevices and methods are shown in U.S. Pat. Nos. 4,488,543; 5,192,327;5,261,911; 5,549,612; 5,713,899; 5,776,196; 6,136,002; 6,159,245;6,224,602; 6,258,089; 6,261,586; 6,264,655; 6,306,136; 6,328,738;6,361,537; and 6,592,586. Some or all of these devices have improved thesuccess rate and have simplified the surgical techniques in inter-bodyvertebral fusion.

U.S. Pat. No. 6,258,089 81 issued Jul. 10, 2001 to Campbell et al. foran Anterior Cervical Plate and Fixation System discloses an anteriorcervical plate, along with threaded fasteners for securing the plate tovertebrae or other osseous material. The cervical plate has severalpockets or apertures. The pockets have spherical surfaces, and thefasteners have heads with similarly sized spherical surfaces, which whenengaged permit each of the fasteners to be oriented at a variety ofprojection angles with respect to the plate. In connection with eachpocket, the cervical plate incorporates a fastener retaining feature.The feature can take the form of a cantilevered tab or a beam supportedat its opposite ends, in each case plastically deformable between anopen position for admitting the fastener and a closed position forpreventing retraction.

U.S. Pat. No. 5,549,612 issued Aug. 27, 1996 to Yapp et al. forOsteosynthesis Plate System discloses an osteosynthesis plate systemthat is particularly well adapted to securely fuse adjacent cervicalvertebrae. The plates are adapted for mounting upon the anterior orposterior surfaces of the vertebrae. Plates for mounting on the anteriorvertebral surfaces have a concave bone contacting surface and a bonescrew locking mechanism integral with each screw hole. Moreover, thebone contacting surface of the plate has a plurality of bone penetratingprotrusions to more securely affix the plate to bone. Plates formounting on the posterior vertebral surfaces also have bone penetratingprotections on their bone contacting surfaces. Such plates are formed soas to have a curved bone contacting surface that is concave in thetransverse axis of the plate and convex in the longitudinal axis of theplate. The screw holes of such plates are constructed so as to guide abone screw along a desired angle to improve the anchoring of the screwsin bone.

One drawback of the plates and screw systems of the past is that theywere relatively complicated to machine and manufacture and oftentimesrequired a large thickness in order to provide enough material that willpermit the plate to be machined to provide the integral arms and locks.

What is needed, therefore, is a screw, system and method that reducesthe number of steps required to attain a screw-plate locked engagementduring a surgical procedure.

SUMMARY OF THE INVENTION

It is, therefore, one object of the invention to provide an integral andcompressible screw, system and method having a screw locking mechanismthat reduces the number of steps required to attain screw-plateengagement and locking during a surgical procedure.

Another object of the invention is to provide a screw locking system andmethod that will locate the locking mechanism on the screw, rather thanthe plate.

Another object of the invention is to provide a screw head having aplurality of screw head portions having internal walls, respectively,that define a plurality of apertures and that cooperate to define afemale working opening, the plurality of apertures causing the screwhead portions to be urged or compressed together upon the insertion of atool so that the screw head can be inserted into an aperture in theplate.

Still another object of the invention is to provide a plate system thatutilizes a screw having a screw head having a plurality of portions thathave camming surfaces that can be used to urge the plurality of portionstogether upon the insertion of a tool into the female working opening.

Still another object of the invention is to provide a system, method andscrew-plate locking mechanism that will permit an improved and simplerplate design and that can, for example, reduce a thickness of the plateor provide other machining and manufacturing advantages.

In one aspect, one embodiment comprises a plate system comprising aplurality of screws, each of the plurality of screws having a shank andthe screw head, a plate having a plurality of apertures for receivingthe plurality of screws, respectively, the plate further comprising aplurality of the detent portions associated with the plurality ofapertures, respectively, the plurality of detent portions defining aplurality of screw head receiving areas associated with the plurality ofapertures, respectively, for receiving at least a portion of the screwhead after the screw is screwed into bone, the at least a portion of thescrew head being adapted to be compressible when the screw is screwedinto bone and expandable so that it can be received in at least one ofthe at least one of the plurality of screw head receiving areas, the atleast a portion of the screw head cooperating with at least one of theplurality of detent portions to restrict or prevent the screw fromwithdrawing from the plate.

In another aspect, another embodiment comprises a method for locking aplurality of screws in a plate and preventing them from withdrawing fromthe plate, each of the plurality of screws comprising a screw head, themethod comprising the steps of providing the plate, the plate having aplurality of apertures and a plurality of receiving areas associatedwith the plurality of apertures, respectively, providing each screw headwith a compressible portion, the compressible portion being resilientand compressible when the screw is screwed into bone and expandable sothat the compressible portion can expand and be received in at least oneof the plurality of receiving areas, the compressible portion of thescrew head of each of the plurality of screws cooperating with at leastone of the plurality of receiving areas to which it is associated andpreventing the screw from withdrawing from the plate.

In still another aspect, another embodiment comprises a bone screw foruse in an implant plate comprising a shank and a bone screw head, thebone screw head comprises a compressible portion, the compressibleportion being resilient an compressible when the screw is screwed intobone and expandable so that the compressible portion can expand and bereceived in at least one of a plurality of receiving areas in theimplant plate, the compressible portion of the bone screw head of eachof the plurality of screws being compressible when the bone screw isscrewed into bone and expandable after it is received in the implantplate in order to prevent the screw from withdrawing from the plate.

In yet another aspect, another embodiment comprises an implant systemcomprising at least one screw having a screw body having a longitudinalslot or aperture along an axis of the screw body to define a pluralityof resilient members, each of the plurality of resilient memberscomprising an internal wall defining a flexible member aperture, atleast a portion of the internal wall defining a camming surface, theflexible member aperture of the plurality of resilient memberscooperating to define a tool insertion aperture having a predeterminedaperture shape, a tool having a working surface having a predeterminedtool shape in cross section that generally complements the predeterminedtool aperture shape, the working surface of the tool engaging thecamming surface and causing the plurality of resilient members to assumea compressed position.

In another aspect, another embodiment comprises a plate systemcomprising a plurality of screws, each of the plurality of screws havinga shank and a screw head, a plate having a plurality of apertures forreceiving the plurality of screws, respectively, the plate furthercomprising a plurality of detents associated with the plurality ofapertures, respectively, at least a portion of the screw head beingadapted to be compressible when the at least one of the plurality ofscrews are screwed into bone and expandable so that it can be receivedin at least one of a plurality of screw head receiving areas, the atleast a portion of the screw head cooperating with at least one of theplurality of detents to restrict or prevent the at least one of theplurality of screws are from withdrawing from the plate.

In still another aspect, another embodiment comprises a method forlocking a plurality of screws in a plate and preventing the plurality ofscrews from withdrawing from the plate, each of the plurality of screwscomprising a screw head, the method comprising the steps of providingthe plate, the plate having a plurality of apertures and a plurality ofreceiving areas associated with the plurality of apertures,respectively, providing each screw head with a compressible portion, thecompressible portion being resilient and compressible when each of theplurality of screws are screwed into bone and expandable so that thecompressible portion can expand and be received in at least one of theplurality of receiving areas, the compressible portion of the screw headof each of the plurality of screws cooperating with the at least one ofthe plurality of receiving areas to which it is associated andpreventing each of the plurality of screws from withdrawing from theplate.

In yet another aspect, another embodiment comprises a bone screw for usein an implant plate comprising a shank and a bone screw head, the bonescrew head comprising a compressible portion, the compressible portionbeing resilient and compressible when the bone screw is screwed intobone and expandable so that the compressible portion can expand and bereceived in a detent of an implant, the compressible portion of the bonescrew head of the bone screw being compressible when the bone screw isscrewed into bone and expandable after it is received in the implantplate in order to prevent the bone screw from withdrawing from theimplant plate.

In still another aspect, another embodiment comprises an implant systemcomprising a plate member having a plurality of screw-receivingopenings, each of the plurality of screw-receiving openings having atleast one plate member detent associated therewith, a plurality ofscrews each having a screw head having a plurality of integralcompressing portions for receipt in the plurality of screw-receivingopenings, respectively; and the plurality of integral compressingportions of each screw expanding after the screw is mounted into boneand cooperating with the at least one plate member detent of at leastone of the plurality of screw-receiving openings to which it isassociated, thereby preventing the screw from withdrawing from the platemember.

This invention, including all embodiments shown and described herein,could be used alone or together and/or in combination with one or moreof the following list of features:

-   -   The plate system wherein the plate system further comprises a        tool having a working surface for compressing at least a portion        of the screw head after at least a portion of the screw head        receives the working surface.    -   The plate system wherein at least a portion of the screw head of        each of the plurality of screws comprises a plurality of        resilient portions having receiving areas that cooperate to        define a female opening for receiving the working surface.    -   The plate system wherein the plurality of resilient portions        each comprise an inner wall that defines the receiving areas        that have a camming surface, respectively, the camming surface        being engaged by at least a portion of the working surface of        the tool when the tool is inserted into the female opening.    -   The plate system as wherein the plate system further comprises a        tool having a working surface, at least a portion of the screw        head comprising a plurality of resilient portions each        comprising an inner wall, at least a portion of the inner wall        defines a camming surface that is adapted to be engaged by the        working surface of the tool to drive the plurality of resilient        portions together to a compressed position when the tool is        inserted into the screw head, the compressed position enabling        the screw head to clear at least one of the plurality of detents        when the screw is inserted into the plate.    -   The plate system wherein each of the plurality of screws        comprise a plurality of resilient portions, each of which are        elastic or resilient and have an inner wall that defines a        projection opening, the projection openings of the plurality of        resilient portions cooperate to define a female opening for        receiving the working surface, at least a portion of the inner        wall defining a camming surface that is adapted to be engaged by        the working surface of the tool when the tool is driven axially        into the female opening until the plurality of resilient        portions are in a compressed position, the compressed position        being dimensioned such that the screw head clears at least one        of the plurality of detents when the screw is inserted into the        plate.    -   The plate system wherein each of the inner walls are generally        U-shaped in cross-section.    -   The plate system wherein the working surface of the tool        comprises a beveled or curved surface for engaging the camming        surface and for causing the plurality of resilient portions to        assume the compressed position.    -   The plate system wherein each of the inner walls comprises a        curved or beveled surface adapted to facilitate introducing the        working surface of the tool into the female opening and for        engaging the camming surface.    -   The plate system wherein the working surface of the tool        comprises a beveled or curved surface for engaging the camming        surface and each of the inner walls comprises a curved or        beveled surface adapted to facilitate introducing and guiding        the working surface of the tool into engagement with the camming        surface.    -   The plate system wherein the plurality of resilient portions are        normally in an unbiased or undeflected home position when the        tool is not inserted into the screw head so that after the screw        head clears at least one of the plurality of detents and the        tool is removed from the female opening, the plurality of        resilient portions return to the unbiased or undeflected home        position, whereupon at least a portion of at least one of the        plurality of resilient portions becomes operatively associated        with at least one of the plurality of detents, thereby locking        the screw in the plate.    -   The plate system wherein each of the camming surfaces extends        generally radially inwardly toward an axis of the screw.    -   The plate system wherein the inner wall is non-circular and        comprises at least one raised or inwardly-projecting projection        surface that defines the camming surface.    -   The plate system wherein when the plurality of resilient        portions are driven toward each other and into a compressed        position, the screw head clears at least one of the plurality of        detents when the screw is inserted into the plate.    -   The plate system wherein the screw head comprises a plurality of        screw head portions each having a female opening, the female        opening cooperating to define a female working opening for        receiving a tool such that when the tool is inserted into the        female working opening the plurality of screw head portions are        driven together to a compressed position.    -   The plate system wherein the inner wall is not circular and        defines or provides a plurality of inner walls in the plurality        of resilient portions, respectively, the plurality of inner        walls having a plurality of camming surfaces, respectively, that        may be engaged by a plurality of working portions of the working        surface of the tool when the tool is inserted into a female        working opening, thereby driving the plurality of screw head        portions together.    -   The plate system wherein each of the plurality of inner walls is        generally U-shaped or Omega-shaped in cross section.    -   The plate system wherein the female working opening defines a        predetermined shape.    -   The plate system wherein the predetermined shape is a figure        eight or bowtie shape.    -   The plate system wherein the tool comprises a predetermined        shape in cross section that is adapted to have engaging surfaces        for engaging the camming surfaces in order to drive the        plurality of screw head portions to the compressed position.    -   The plate system wherein the tool predetermined shape is a        figure eight or bowtie shape in cross section.    -   The plate system wherein the plurality of detents comprise a        plurality of undercut walls, respectively, that define a        plurality of undercuts associated with the plurality of        apertures, respectively, each of the plurality of undercut walls        defining a receiving area for receiving at least a portion of        the plurality of resilient portions.    -   The plate system wherein each of the plurality of detents        defines a generally U-shaped wall that defines an undercut        associated with each of the plurality of apertures, the        generally U-shaped wall defining a generally U-shaped receiving        area for receiving at least a portion of the plurality of        resilient portions.    -   The plate system wherein the screw head comprises a concaving or        separating area that defines each of a plurality of elongated        members, each of the plurality of elongated members being        resilient, elastic or movable so that they can be moved toward        each other in response to axial insertion of a working surface        of a tool into the screw head.    -   The plate system wherein the plurality of screw head portions        comprises inner walls that cooperate to define a female working        opening, the inner walls also having at least one camming        surface that engages and are driven by a working surface of the        tool to a compressed position when the working surface is        inserted axially into the female working opening.    -   The plate system wherein the plurality of screw head portions        extend generally longitudinally and parallel to an axis of the        shank.    -   The plate system wherein the plurality of screw head portions        comprises a first portion that generally opposes a second        portion.    -   The method wherein the compressible portion comprises a        plurality of screw head portions each having an inner wall that        defines a receiving area, the receiving area of the screw head        portions cooperating to define a female opening for receiving a        working surface of a tool, the method further comprises the step        of axially inserting the working surface of the tool into the        female opening so that the working surface of the tool can        engage and to cause the plurality of screw head portions to        become situated in a compressed position.    -   The method wherein the inner wall has a camming surface that        engages the working surface of the tool when the tool is        inserted into the female opening.    -   The method wherein both the female opening and the working        surface comprise a figure eight or bowtie shape, and the working        surface has at least one beveled surface that engages the        camming surface when the tool is inserted into the female        opening.    -   The bone screw wherein the compressible portion comprises a        plurality of screw head portions that are compressible or        movable toward an axis of the bone screw and to a compressed        position in response to a tool being inserted into the screw        head.    -   The bone screw wherein each of the plurality of screw head        portions have an inner wall or surface defining a receiving        area, the receiving area of the plurality of screw head portions        cooperating to define a female opening adapted to receive the        tool and drive the plurality of screw head portions to the        compressed position in response to movement of the tool into the        female opening.    -   The bone screw wherein the inner wall or surface is generally        U-shaped or Omega-shaped in cross-section that is generally        radial with respect to an axis of the bone screw.    -   The bone screw wherein the female opening defines a        predetermined shape.    -   The bone screw wherein said predetermined shape is a figure        eight, bowtie shape or Omega shape.    -   The bone screw wherein at least one of the inner wall or surface        comprises a camming surface against that a portion of the tool        engages to cause the plurality of screw head portions to be        situated in the compressed position.    -   The bone screw wherein each of the plurality of screw head        portions are elastic or resilient and have an inner wall that        defines an opening, the opening of the plurality of screw head        portions cooperate to define a female tool-receiving opening for        receiving a working surface of the tool, at least a portion of        the inner wall defining a camming surface that is adapted to be        engaged by the working surface of the tool when the tool is        inserted axially into the female tool-receiving opening, thereby        driving the plurality of screw head portions into a compressed        position when the bone screw is inserted into the implant plate.    -   The bone screw wherein each of the inner walls comprises a        curved or beveled surface adapted to facilitate introducing the        working surface of the tool into the female tool-receiving        opening and into engagement with the camming surface.    -   The bone screw wherein the working surface of the tool comprises        a beveled or curved surface for engaging the camming surface.    -   The bone screw wherein the plurality of screw head portions are        normally in an unbiased or undeflected home position when the        tool is not inserted into the bone screw head so that after the        bone screw head is inserted into a plate having at least one        detent associated with at least one aperture in the implant        plate and the tool is removed from the female tool-receiving        opening, the plurality of screw head portions return to the        unbiased or undeflected home position, whereupon at least a        portion of at least one of the plurality of screw head portions        becomes operatively associated with at least one detent, thereby        locking the screw in the plate.    -   The bone screw wherein the camming surface extends generally        radially inwardly toward an axis of the bone screw.    -   The bone screw wherein the inner wall is non-circular and        comprises at least one raised or inwardly-sloped projection        surface that defines the camming surface.    -   The bone screw wherein the plurality of screw head portions are        dimensioned such that when they are in the compressed position        the bone screw head clears at least one detent in a plate in        which the bone screw is inserted.    -   The bone screw wherein each of the plurality of screw head        portions is generally elongated and has an axis that is        generally parallel to an axis of the shank.    -   The bone screw wherein the bone screw head has an interrupted or        discontinuous inner wall that defines a plurality of female        openings in the plurality of screw head portions, respectively,        the plurality of female openings cooperating to define a female        working opening for receiving the tool such that when the tool        is inserted into the female working opening the plurality of        screw head portions are driven together to reduce a dimension of        the bone screw head.    -   The bone screw wherein said each of the plurality of inner walls        has a camming surface that may be engaged by a working surface        of the tool when the tool is inserted into the female working        opening thereby driving the plurality of screw head portions        together to a compressed position.    -   The bone screw wherein each of the plurality of inner walls is        generally U-shaped or Omega-shaped in cross section.    -   The bone screw wherein the inner walls cooperate to define the        female working opening having a predetermined shape that is        adapted to receive a working end of the tool which has a        generally complementary shape so that when the tool is inserted        into the female working opening, the plurality of screw head        portions are driven to the compressed position and the tool can        simultaneously be used to screw the bone screw into bone.    -   The bone screw wherein the predetermined shape is a figure eight        or bowtie shape.    -   The bone screw wherein the screw head comprises a concavity or        separating area for defining a plurality of generally parallel        elongated members, each of the plurality of elongated members        being resilient or elastic so that they can be moved or driven        in response to an axial insertion of a working surface of a tool        into a female opening in order to reduce an overall dimension of        the bone screw head so that it can be inserted into the implant        plate.    -   The bone screw wherein the plurality of screw head portions are        elongated and comprise an axis that is generally parallel to an        axis of the bone screw.    -   The bone screw wherein the plurality of screw head portions        comprises a first portion that generally opposes a second        portion.    -   The bone screw wherein each of the plurality of screw head        portions comprise a first end integrally formed in the shank of        the bone screw and a free end that is adapted to be moved toward        and away from an axis of the bone screw.    -   The bone screw wherein the plurality of screw head portions        comprises a first portion that generally opposes a second        portion, a second end of the first portion and a second end of        the second portion each comprising an inner wall surface that        defines a first portion opening and a second portion opening,        respectively, that cooperate to define a female opening, each of        the inner wall surfaces having a camming surface that is adapted        to be engaged and driven by a tool in order to drive the first        and second portion to a compressed position.    -   The bone screw wherein the working surface of the tool        substantially simultaneously engages the camming surface of at        least one inner wall surface, each inner wall surface comprising        a plurality of camming surfaces.    -   The bone screw wherein the working surface substantially        simultaneously engages the plurality of camming surfaces of the        inner wall surface of each of a plurality of screw head        portions.    -   The implant system wherein the implant system further comprises        a tool having a working surface for compressing the plurality of        integral compressing portions when the working surface is        inserted into at least a portion of the screw head.    -   The implant system wherein the plurality of integral compressing        portions cooperate to define a female opening for receiving the        working surface.    -   The implant system wherein the plurality of integral compressing        portions each comprise an inner wall that defines a        tool-receiving area, the tool-receiving area cooperating to        define the female opening, the inner wall also having a camming        surface that is engaged by the working surface of the tool when        the tool is inserted into the female opening.    -   The implant system wherein the implant system further comprises        a tool having a working surface, the plurality of integral        compressing portions each comprising an inner wall that defines        a tool-receiving opening, at least a portion of the inner wall        defines a camming surface that is adapted to be engaged by the        working surface of the tool to drive the plurality of integral        compressing portions together to a compressed position when the        working surface is inserted into the tool-receiving opening.    -   The implant system wherein each of the plurality of integral        compressing portions are elastic or resilient and have an inner        wall that defines a tool-receiving opening, the tool-receiving        opening of the plurality of integral compressing portions        cooperating to define a female opening for receiving the working        surface of the tool, at least a portion of the inner wall        defining a camming surface that is adapted to be engaged by the        working surface of the tool when the tool is driven axially into        the female opening until the plurality of integral compressing        portions are in a compressed position.    -   The implant system wherein the working surface of the tool        comprises a tool beveled edge or curved surface for engaging the        camming surface of the inner wall of each of the plurality of        integral compressing portions.    -   The implant system wherein each of the inner walls comprises an        inner wall curved or beveled surface adapted to engage the tool        beveled edge or curved surface to facilitate introducing the        working surface into the tool-receiving opening and into        engagement with the camming surface.    -   The implant system wherein the working surface of the tool        comprises a tool beveled edge or curved surface for        substantially simultaneously engaging the camming surface and        each of the inner walls comprises an inner wall curved or        beveled surface adapted to facilitate introducing and guiding        the working surface of the tool into engagement with the camming        surface.    -   The implant system wherein the plurality of integral compressing        portions are normally in an unbiased home position when the tool        is not inserted into the screw head so that after the screw head        clears at least one plate member detent and the tool is removed        from the female opening, the plurality of integral compressing        portions return to the unbiased home position, whereupon at        least a portion thereof becomes operatively associated with or        generally opposed to at least one plate member detent, thereby        locking the screw in the plate member.    -   The implant system wherein each camming surface extends        generally radially inwardly toward an axis of at least one of        the plurality of screws.    -   The implant system wherein the inner wall is non-circular and        comprises at least one raised or inwardly sloped projection        surface that defines the camming surface.    -   The implant system wherein the plurality of integral compressing        portions are driven toward each other in response to the tool        being inserted into the tool-receiving opening, the plurality of        integral compressing portions are driven to a compressed        position and a radial dimension of the screw head is reduced.    -   The implant system wherein the tool-receiving opening is        generally U-shaped, Omega-shaped or C-shaped in cross-section.    -   The implant system wherein the screw head has an interrupted or        discontinuous inner wall that defines a plurality of        tool-receiving openings in the plurality of integral compressing        portions, respectively, the plurality of tool-receiving openings        cooperating to define a female working opening for receiving the        working surface of the tool such that when the working surface        is inserted into the female working opening, the plurality of        integral compressing portions are driven together do reduce a        dimension of the screw head.    -   The implant system wherein the interrupted or discontinuous        inner wall is not circular and defines a plurality of inner        walls in the plurality of integral compressing portions, each of        the plurality of inner walls having a plurality of camming        surfaces, respectively, that may be substantially simultaneously        engaged by the working surface of the tool when the tool is        inserted axially into the female working opening, thereby        driving the plurality of integral compressing portions together        to a compressed position.    -   The implant system wherein each of the plurality of inner walls        is generally U-shaped, Omega-shaped or C-shaped in cross        section.    -   The implant system wherein the plurality of inner walls of the        plurality of integral compressing portions cooperate to define        the female working opening having a predetermined shape.    -   The implant system wherein the predetermined shape is a general        figure eight or bowtie shape.    -   The implant system wherein the tool comprises a predetermined        shape in cross section that is adapted to have engaging surfaces        for engaging the camming surfaces in order to drive the        plurality of integral compressing portions to the compressed        position.    -   The implant system wherein the predetermined shape is a general        figure eight or bowtie shape in cross section.    -   The implant system wherein at least one plate member detent        defines an undercut associated with at least one of the        plurality of screw-receiving openings.    -   The implant system wherein at least one plate member detent        defines a continuous undercut channel associated with each of        the plurality of screw-receiving openings.    -   The implant system wherein each of the plurality of integral        compressing portions is generally elongated and resilient or        elastic and adapted to be moved toward each other to a        compressed position and adapted to define a non-circular female        working opening for receiving a complementary-shaped working        area of a tool when the tool is inserted axially into said        non-circular female working opening.    -   The implant system wherein the plurality of integral compressing        portions cooperate, when compressed to a compressed position, to        define a female working opening adapted to receive a tool.    -   The implant system wherein the plurality of integral compressing        portions comprises a first elongated detent that generally        opposes a second elongated detent.    -   The implant system wherein the first and second elongated        detents comprise ends each having an inner wall that defines a        tool-receiving aperture that cooperate to define a female        aperture, the inner walls having a camming surface that faces        the plurality of integral compressing portions together when the        tool is received in the female opening.

These and other objects and advantages of the invention will be apparentfrom the following description, the accompanying drawings and theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective, exploded view of a screw, system and method inaccordance with one embodiment of the invention;

FIG. 2 is a fragmentary view illustrating a tool in operativerelationship with a compressible head on the screw;

FIG. 3 is a fragmentary view illustrating a screw being received in aplate;

FIG. 4 is a fragmentary view illustrating a portion of the screw beingcompressed after the screw is received in the tool and as the screw isscrewed into the bone;

FIG. 5 is a view of the screw after the tool is removed from the screwhead, illustrating the screw head expanding to an expanded and lockedposition where a surface of at least a portion of the screw head becomesgenerally opposed to at least one detent, such as a lip, associated witha screw receiving aperture in the plate;

FIG. 6 is a sectional and fragmentary view illustrating details of oneof a plurality of receiving areas in the plate;

FIG. 7 is a fragmentary view of the screw in a non-compressed state,illustrating various dimensions and configurations of the screw head;

FIG. 8 is a view of the plate illustrating one of the screws locked inthe plate after it is driven into bone;

FIG. 9 is a plan view of a screw head in accordance with one embodimentof the invention illustrating an internal concavity or aperture in thescrew head which defines a compressible portion on the screw head in theform of a compressible pair of screw head portions each having a maleprojection;

FIG. 10 is a view of the embodiment in FIG. 9 after at least a portionof the screw has been compressed, illustrating the projectionscooperating to provide a working surface that can be engaged by a tooland rotatably driven;

FIG. 11 is a view of another embodiment illustrating the internalconcavity in the screw head defining four head portions each having amale projection in a non-compressed state;

FIG. 12 is a view of the alternate embodiment shown in FIG. 11 after thescrew head has been compressed, showing the male projections cooperatingto define a drivable working surface that can be received in the tooland rotatably driven;

FIG. 13 is a view similar to FIGS. 9 and 11 showing still anotherembodiment of a screw head in a non-compressed state, with the internalconcavity in the screw head defining three screw head portions with eachhaving male projections;

FIG. 14 is another plan view of the screw head shown in FIG. 13 after ithas been compressed to a compressed state and showing the maleprojections cooperating to define a working surface or projection thatcan be received in and driven by the tool;

FIG. 15 is a perspective, exploded view of a screw and plate system andmethod in accordance with another embodiment of the invention;

FIGS. 16A-16C are perspective views illustrating the insertion of aworking surface of a tool into a female working opening of variousportions of a screw head of the screw;

FIGS. 17A-170 are fragmentary exploded views illustrating the variouspositions of the screw head portions and insertion of the tool into thescrew head and the closing of the screw head portions in responsethereto;

FIGS. 18A and 188 are sectional and fragmentary views illustratingdetails of one of a plurality of receiving areas in the plate and theinsertion and seating of the screw into the plate;

FIG. 19 is a partially broken perspective view illustrating variousfeatures of the tool;

FIG. 20 is a sectional view, taken along the line 20-20 in FIG. 19,showing a cross-sectional shape of the tool of FIG. 19;

FIG. 21A is a cross-sectional view, taken along the line 21A-21A in FIG.170, illustrating various features of the camming surfaces;

FIG. 218 is a cross-sectional view, taken along the line 218-218 in FIG.170, illustrating features of an internal wall defining an aperture inone of the screw head portions;

FIG. 22 is a cross-sectional view, taken along the line 22-22 in FIG.178, illustrating the tool slightly inserted into the screw headportions; and

FIG. 23 is a view, taken along the line 23-23 in FIG. 170, illustratingthe screw head portions in a closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1-14, a system 10 and tool-actuated locking screwmechanism and locking method are shown. The system 10 comprises a plate12 having a plurality of apertures 14, 16, 18 and 20. The plate 12 maycomprise more or fewer apertures if desired and may comprise at leastone or a plurality of windows 23 for viewing a graft area (not shown)between two vertebrae to be fused together in a manner conventionallyknown.

The plurality of apertures 14-20 each comprise an undercut or interiorand generally U-shaped wall 22, 24, 26 and 28, respectively, that definea plurality of receiving areas, apertures or undercuts 22 a, 24 a, 26 aand 28 a whose purpose and function will be described later herein. Forease of illustration, a sectional fragmentary view of the receiving area22 a is shown and described later herein relative to FIG. 6.

The system 10 comprises at least one or a plurality of screws 30 forsecuring the plate 12 to at least one or a plurality of vertebrae (notshown). For ease of illustration, a single screw 30 is shown anddescribed, and it should be understood that in the example, a singlescrew 30 is received in each of the plurality of apertures 14-20. Asshown in FIG. 1, each screw 30 comprises a shank or threaded portion 32and a screw head 34. The screw head 34 comprises at least a portion thatis adapted to be elastic, resilient or compressible and define acompressible portion 36. In the embodiment being described, thecompressible portion 36 comprises a first elongated portion or resilientportion 36 a and a generally opposing second elongated portion orresilient portion 36 b as shown. Note that the dimension or diameter D1(FIG. 7) of the elongated portion 36 b is slightly smaller than adiameter D2 (FIG. 1) of the threaded portion 32. The benefit of thisdesign is described later herein.

The screw head 34 further comprises a first head portion 38 a that isintegrally formed with the first elongated portion 36 a as shown and asecond head portion 38 b that is integrally formed with the secondelongated portion 36 b as shown. The first and second male projections40 and 42 are integrally formed with the head portion 38 a and 38 b,respectively, as shown and extend generally longitudinally in adirection that is generally parallel to an axis of the head.

The system 10 also comprises a tool 44 having a female working opening46 (FIG. 2) that is adapted to receive and move or compress the firstand second male projections 40 and 42 toward each other and toward anaxis of the screw 30 when the tool 44 is mounted thereon. The tool 44comprises an end 44 a having an interior recessed area or wall 46 b thatdefines the female aperture or female working opening or area 46. Asmentioned, this female working opening 46 is adapted and sized toreceive the male projections 40 and 42 and compress them together. Notethat the female working opening 46 is adapted, sized and has a shapethat generally complements the shape of the male projections 40 and 42when they are compressed together.

Note that the tool 44 comprises one or more beveled surfaces or chamfers48 and 50 in communication with the wall 44 b that facilitate guidingends or surfaces 40 a and 42 a (FIG. 1) into the female working opening46 and compressing the male projections 40 and 42, respectively, andguiding them toward each other and toward an axis A (FIG. 5) of thescrew 30. The tool 44 comprises a shaft 52 which is coupled to orintegrally formed with a handle 54 for gripping and rotating the tool 44and screwing the screw 30 into bone. The tool shaft 52 may be of anydesired length, a tool (not shown) with multiple interchangeable shafts(not shown) may be provided, or multiple tools (not shown) having shafts52 of different lengths.

Returning to the illustration in FIG. 1, it should be understood thatthe first and second elongated portions 36 a and 36 b are compressible,resilient and elastic and movable in the direction of double arrow X(FIG. 7) and is adapted to permit compression of at least a portion ofthe screw head 34 when the tool 44 is engaged with or mounted on thescrew head 34. As will be described later herein relative to FIGS. 3-14,removal of the tool 44 from the first and second male projections 40 and42 results in spontaneous expansion of the at least a portion 36 of thescrew head 34, as illustrated in FIGS. 4-5. In the illustration beingdescribed, the first and second elongated portions 36 a and 36 b areelastic and/or resilient and adapted to permit the first and second headportions 38 a and 38 b, respectively, to move toward each other when thetool 44 is mounted thereon and then permit the first and second maleprojection portions to decompress, expand or move away from each otherwhen the tool 44 is removed from the screw head 34 in the mannerdescribed herein.

As mentioned earlier, the plate 12 comprises the plurality of apertures14-20 having the associated recessed area or internal concavities 22a-28 a, respectively, mentioned earlier. For ease of illustration, thewall 22 and associated receiving area 22 a will be shown and describedrelative to FIG. 6, but it should be understood that each of the otherrecessed areas or receiving areas 24 a-28 a are similarly constructed.As illustrated in FIG. 6, the plate 12 has a generally cylindrical wall56 that defines a generally cylindrical portion or exit area 14 a of theaperture 14. Note that the generally cylindrical portion 14 a has adiameter D3 (FIG. 6) that is slightly larger than the diameter D2(FIG. 1) of the threaded portion 32 of screw 30, but smaller than thediameter D4 (FIG. 7) of the screw head portions 38 a and 38 b when theyare in either a compressed or non-compressed state.

The plate 12 further comprises a frusto-conical wall 58 that couples thesurface or wall 22 to a radial wall, lip or seat 59 (FIG. 6). The walls58 and 59 cooperate and are adapted and sized to provide or define aseat for receiving the tapered walls or surfaces 38 a 1 and 38 b 1associated with the screw head portions 38 a and 38 b, respectively.

The plate 12 comprises a plurality of detents or lips 60, 62, 64 and 66(FIG. 1) that are integral with the walls 22-28, respectively. Theplurality of detents or lips 60, 62, 64 and 66 cooperate with theplurality of walls 22-28, respectively, to define the undercuts ordefine radial annular part of areas 22 a-28 a. For ease of illustration,the operation and function of the screw head receiving area 22 a andscrew 30 will now be described relative to FIGS. 3-7.

In general and as illustrated, the tool 44 (FIGS. 2-4) is mounted on thefirst and second male projections 40 and 42, which compresses themtogether as shown in FIGS. 3 and 4. The tool 44 is rotated to screw thescrew 30 into bone after the screw 30 is received in the•aperture 14 ofplate 12. The first and second portions 38 a and 38 b of screw head 34comprises surfaces 38 a 1 and 38 b 1, respectively. After these surfaces38 a 1 and 38 b 1 move past or clear (FIGS. 4 and 5) the lip or detent60, the tool 44 may be removed (FIG. 5) from the screw head 34. When thetool 44 is removed from the first and second male projections 40 and 42,the first and second elongated portions 36 a and 36 b cause the firstand second screw head portions 38 a and 38 b to de-compress or expandinto the receiving area, aperture or undercut 22 a, as illustrated inFIGS. 4-5.

As illustrated in FIGS. 5 and 7, the screw head 34 has an expanded widthor screw head diameter dimension D4 (FIG. 7) and a compressed dimensionD5 (FIGS. 3 and 4). The wall 22 comprises a wall diameter D6 (FIG. 6)which is larger than the receiving opening dimension or diameter D7(FIG. 6) defined by an inner surface 60 b of the lip or detent 60. Inthe illustration, dimension D4 (FIG. 7) is larger than dimension D5(FIG. 4), but smaller than the dimension D6 (FIG. 6), while thecompressed dimension D5 is smaller than both the dimension D6 and thedimension D7. This permits the screw head 34 to be received in theaperture 14 and clear the lip 60 when the portions 38 a and 38 b arecompressed, yet be retained by the lip 60 when the portions 38 a and 38b are in the non-compressed or expanded state (FIG. 5).

Thus, the tool 44 is mounted on the male projections 40 and 42 of thescrew head 34 to compress the screw head 34 by moving the portions 38 aand 38 b toward each other and toward the axis A (FIG. 5) of the screw30. The compressed dimension D5, illustrated in FIG. 3, is slightlysmaller than the receiving opening dimension D5 so that as the tool 44is rotated, the screw head 34 clears the lip 60 as the screw 30 becomesscrewed into bone. The screw 30 is screwed into bone until the shouldersor surfaces 38 a 1 and 38 b 1 clear or move past the surface 60 a of thelip 60 as illustrated in FIGS. 3-5. Thereafter, the tool 44 may beremoved from the screw head 34 (FIG. 5) which permits the portions 38 aand 38 b of screw head 34 to resiliently or elastically expand until thesurfaces 38 a 2 and 38 b 2 (FIG. 7) become generally opposed to thesurface 60 a of the internal lip or detent 60 as shown in FIG. 5. Noticein FIG. 5 that when this occurs, the surfaces 38 a 2 and 38 b 2cooperate with that surface 60 a to retain and lock the screw 30 in theplate 12 and prevent the screw 30 from withdrawing, for example, in anaxial direction away from the bone (i.e., to the right as viewed in FIG.5).

Note in FIG. 5 that the diameter or dimension 01 (FIG. 7) of the screw30 in the elastic or resilient portions 36 a and 36 b defines an area orregion 37 (FIG. 1) of flexion. This dimension 01 in region 37 isslightly smaller in diameter or cross-section than the diameter ordimension 02 (FIG. 1) of the threaded portion 32. This prevents externalbone from engaging and/or compressing the resilient portions 36 a and 36b which could interfere with the elastic or resilient re-expansion ofthe resilient portions 36 a and 36 b after the tool 44 has been removedfrom the screw head 34 as illustrated in FIGS. 4 and 5.

At this point, the surfaces 38 a 2 and 38 b 2 clear the annular seat orlip 59 before the screw 30 bottoms out. The surgeon then releases thetool 44 and the screw head 34 re-expands. The bottom surface 41 (FIG. 7)of the screw engages the annular seat or lip 59, thereby preventing thescrew 30 from travel.

In the illustration being described, note that the screw 30 comprises aconcavity 70 (FIGS. 1, 2, 9 and 10) that defines the generally opposingfirst and second elongated portions 36 a and 36 b and the screw headportions 38 a and 38 b as shown. As mentioned earlier, the first andsecond male projection portions 40 and 42 of the screw head 34 areadapted, sized and shaped to provide a rotatably drivable workingsurface when they are compressed by the working end 44 a of the tool 44.In this regard, when the male projections 40 and 42 are compressedtoward each other, as illustrated in FIG. 10, they define a generallypolygonal shape, such as a rectangular or square shape. The maleprojections 40 and 42 may also be adapted, sized and shaped to anydesired configuration that will enable the at least a portion 36 of thescrew head 34, such as the male projections 40 and 42, to be compressedtoward the axis of screw 30 or toward each other so that they can bereceived in the female working opening or area 46 of tool 44 androtatably driven. Similarly, the interior wall 44 b that defines thefemale aperture or female working opening 46 is adapted, sized andshaped so that it complements the shape of the compressed maleprojections 40 and 42, so that the male projections 40 and 42 can berotatably driven by the tool 44 in order to screw the screw 30 intobone, although not shown,

The concavity 70 or separating area may comprise one or more separatingareas to define the pair of elongated portions 36 a and 38 a. FIGS. 9and 10 illustrate the screw 30 having the screw head 34 and concavity 70that provides or defines the pair of generally opposing male projections40 and 42 as shown. Again, note that when the screw head portions 38 aand 38 b are compressed together, the male projections 40 and 42 havesurfaces 40 a, 40 b, 40 c and 42 a, 42 b and 42 c (FIGS. 9 and 10) thatcooperate to define the generally rectangular (as viewed in FIG. 10)projection that is received in the working end 44 a of the tool 44.

FIGS. 13 and 14 illustrate another embodiment showing a screw 30 havinga screw head 34′ concavity 72 defining three posts, portions or maleprojections 30 c′, 30 d′ and 30 e′ shown in an expanded state in FIG.13. Note that when the screw head portions 38 c′, 38 d′ and 38 e′ arecompressed toward each other and toward an axis of the screw 30, theassociated surfaces of male projections 38 c 1′, 38 d 1′ and 38 e 1′,respectively, and associated surfaces cooperate to define a generallyrectangular or polygonal shape. They are adapted to be received by theworking end 44 a of the tool 44 which has the female aperture or femaleworking opening 46, which is adapted and sized to complement the shapeof the male projections when they are compressed so that the tool 44 canrotatably drive and screw the screw 30′ into bone.

FIGS. 11 and 12 illustrate yet another illustrative embodiment showing ascrew head 34″ concavity 74 that defines four generally elongatedportions 38 f′, 38 g″, 38 h″ and 38 i″. In this embodiment, each of thefour elongated portions 38 f-38 i′ comprises the male projectionsportions 38 f 1″, 38 g 1″, 38 h 1″ and 38 i 1″ as shown in FIG. 11. FIG.11 illustrates the screw head portions 38 f′-38 i″ in theirnon-compressed or expanded state when they are not engaged by the tool44. In contrast, FIG. 12 illustrates the compressed state of the screwhead portions 38 f′-38 i″ after the tool 44 is placed on the maleprojection portions 38 f 1″-38 i 1″ in the manner described earlierherein. Again, it is important to note that the side wall or surfaces ofthe male projection portions 38 f 1″-38 i 1″ cooperate to define aworking surface, such as a polygonal, hexagonal, rectangular or squaresurface that cooperates with and is adapted to be received in the femaleaperture or female working opening 46 of the tool 44 which has acomplementary shape so that the tool 44 can rotatably drive and screwthe screw 30 into bone.

While the embodiments shown and described relative to FIGS. 1-14illustrate two portions 38 a and 38 b (FIGS. 9 and 10), three portions30 c′, 30 d′ and 30 e′ (FIGS. 13 and 14) and four portions 38 f′, 38 g″,38 h″ and 38 i″ (FIGS. 11 and 12), it should be understood that thescrew head 34 could be provided with a concavity that defines moreprojection portions if desired.

Returning now to FIG. 6, note that the undercut or receiving area 62provides a continuous undercut or receiving area 22 a about the aperture14. It should be understood that while the lip 60 in the embodimentbeing described defines a continuous annular surface 60 a surroundingthe aperture 14. This lip 60 could also be discontinuous to provide atleast one or a plurality of detents that cooperate with one or more ofthe surfaces 38 a 2 and 38 b 2 (FIG. 7) to lock the screw 30 in theplate 12.

Advantageously, a benefit to the embodiments being described herein is areduction in the number of steps required to remove the screw from theplate screw-plate engagement during a surgical procedure. In thisregard, the disengagement of the locking of the screw 30 in the plate 12occurs when the tool 44 is mounted on the screw head 34. Many prior artsystems, for example, require multiple tools, for example, one tool torelease the screw lock and another tool to screw the screw.

Moreover, many prior art mechanisms comprised a locking mechanismembodied in the plate or on the plate, whereas the locking mechanism inthe illustration being described is embodied and integral with screw 30rather than the plate. Advantageously, this allows for simpler platedesigns. This also permits the plates being made thinner, which is agoal of surgical plate development.

Referring now to FIGS. 15-188, another embodiment of the invention isshown. In this embodiment a system 100 and tool-actuated locking screwmechanism are shown. In this embodiment, the locking screw mechanismcomprises a plate 112 having a plurality of apertures 114, 116, 118 and120 as shown. The plate 112 may comprise more or fewer apertures ifdesired and may comprise at least one or a plurality of windows 123 forviewing a graft area (not shown) between two vertebrae to be fusedtogether in a manner conventionally known.

The plurality of apertures 114-120 each comprise an undercut or interiorand generally U-shaped wall or channel 122, 124, 126 and 128,respectively, that defines a plurality of apertures, undercuts orreceiving areas 122 a, 124 a, 126 a and 128 a whose purpose and functionwill be described later and which function similar to the receivingareas 22 a, 24 a, 26 a and 28 a described earlier herein relative to thefirst embodiment. For ease of illustration, a sectional fragmentary viewof wall or channel 122 and receiving area 122 a is shown and describedlater herein relative to FIGS. 18A-18B.

The system 100 comprises at least one or a plurality of screws 130 forsecuring the plate 112 to at least one or a plurality of vertebrae (notshown). For ease of illustration, a single screw 130 is shown anddescribed and it should be understood that in the example, a singlescrew 130 is received in each of the plurality of apertures 114-120. Asshown in FIGS. 15 and 16A-160, 17A-17D, 18A-18B and 21A-21B, each screw130 comprises a threaded portion or shank 132 and a screw head 134. Thescrew head 134 comprises at least a portion that is adapted to beelastic, resilient or compressible and defines a compressible, elasticor resilient portion 136. In the embodiment being described, thecompressible, elastic or resilient portion 136 comprises a resilientportion or elongated portion 136 a and a generally opposing secondelongated portion or resilient portion 136 b as shown. Note that thedimension or diameter of the compressible, elastic or resilient portion136 may be slightly smaller than a diameter of the threaded portion 132for the reasons described earlier herein relative to the firstembodiment.

The screw head 134 further comprises a first head portion 138 a that isintegrally formed with the first elongated portion 136 a as shown and asecond head portion 138 b that is integrally formed with the secondelongated portion 136 b as shown. The first and second head portions 138a and 138 b each comprise an interior wall 138 a 1 and 138 b 1 thatdefine a female member opening or aperture 140 and a second femalemember opening or aperture 142 as best illustrated in FIG. 17A. In theembodiment being described, the apertures 140 and 142 defined by theinternal walls 138 a 1 and 138 b 1 cooperate to define a female opening,slot or female working opening 143 for receiving a tool 144 that will bedescribed later herein. The first and second head portions 138 a and 138b are defined by a concavity or separating area 170 that defines andseparates the first head portion 138 a and the second head portion 138b.

Note that the internal wall 138 a 1 comprises a first camming surface138 b 2 and a second camming surface 138 b 3 that is joined by agenerally flat or planar surface 138 b 4. Likewise, the interior wall138 b 1 of the second head portion 138 b comprises or defines a firstcamming surface 138 b 2, a second camming surface 138 b 3 that arejoined by a generally planar or flat surface 138 b 4 as shown.

Note that the interior walls 138 a 1 and 138 b 1 comprise a curved,chamfer, beveled or angled surface 137 and 139, respectively, forfacilitating insertion of the tool 144 in the manner described laterherein. In general, and as illustrated in FIGS. 15 and 16A-16C, notethat when the tool 144 is inserted into the female working opening 143,the first and second head portions 138 a and 138 b are driven or urgedtogether so that the overall dimension of the screw head 134 is reducedso that it can be inserted into the plate 112 in the manner describedlater herein. Note that the first and second female member openings orapertures 140 and 142 cooperate to define a general bowtie, butterfly orfigure-eight shape, especially when the first and second head portions138 a and 138 b are in the open or closed position as illustrated inFIG. 170. Note also the internal walls 138 a 1 and 138 b 1 are generallyOmega-shaped or U-shaped in cross-section and define an opening such asthe curved, chamfer, beveled or angled surface 139 (FIG. 21B) into thefemale member opening or aperture 140.

Referring now to FIGS. 19 and 20, note that the system 100 comprises atool 144 having a handle 144 a and a male working surface 144 b. Notethat the male working surface 144 b also comprises a curved, chamfer,beveled or angled surface 144 c (FIG. 19) that cooperates with thecurved, chamfer, beveled or angled surfaces 137 and 139 to guide thetool 144 into the female working opening 143 (FIG. 15). It should beunderstood that when the male working surface 144 b is inserted into thefemale working opening 143, the curved, chamfer, beveled or angledsurface 144 c engages and cooperates with at least a portion of thecurved, chamfer, beveled or angled surfaces 137 and 139 to urge, driveor move the first and second head portions 138 a and 138 b toward eachother as illustrated in FIGS. 16A-16C and 17A-17D and toward an axis A1(FIG. 17A) of the screw 130.

The tool 144 comprises a tool shaft 144 d which is coupled to orintegrally formed with the handle 144 a for gripping and rotating thetool 144 and screwing the screw 130 into bone. The tool shaft 144 d maybe of any desired length, a tool (not shown) with multipleinterchangeable shafts (not shown) may be provided, or multiple tools(not shown) having shafts 144 d of different lengths.

As with the embodiments described earlier herein, it should beunderstood that the first and second elongated portions 136 a and 136 bare compressible, resilient and elastic and movable in the direction ofdouble arrow X1 (FIG. 17C) and is adapted to permit compression of atleast a portion of the screw head 134 when the tool 144 is received inor mounted in the screw head 134 by inserting the male working surface144 b into the female working opening 143 (FIG. 15).

As with the embodiments described earlier relative to FIGS. 1-14, thefirst and second elongated portions 136 a and 136 b are elastic and/orresilient and movable and adapted to permit the first and second headportions 138 a and 138 b, respectively, to move toward and away fromeach other when the male working surface 144 b of the tool 144 isinserted into the female working opening 143 (FIG. 15), thereby causingthe first and second head portions 138 a and 138 b to move toward eachother as illustrated in FIGS. 17A-17D. When the male working surface 144b is removed from the female working opening 143, the first and secondelongated portions 136 a and 136 b and the first and second headportions 13 a and 138 b decompress, expand or move away from each otherand return to their home position, which is illustrated in FIGS. 15 and17A.

Referring to FIGS. 14 and 18A-188, the plate 112 comprises the pluralityof apertures 114-120 having the associated recessed area or internalconcavities 122 a-128 a, respectively. For ease of illustration, thewall or channel 122 and associated receiving area 122 a will be shownand described relative to FIGS. 18A and 188, but it should be understoodthat each of the other recessed areas or receiving areas 124 a-128 a aresimilarly constructed. As illustrated in FIG. 18A, the plate 112 has agenerally cylindrical wall 156 that defines a generally cylindricalportion or exit area 114 a of the aperture 114. Note that the generallycylindrical portion 114 a has a diameter that is slightly larger thanthe diameter of the threaded portion 132 of the screw 130, but smallerthan the diameter of the screw head portions 138 a and 138 b when theyare in either a compressed or decompressed state.

The plate 112 further comprises a frusto-conical wall 158 that couplesthe surface or wall 122 to the generally cylindrical wall 156 to definea seat or area 159. The walls 158 and 122 cooperate and are adapted insize to provide or define a seat for receiving tapered walls or surfaces138 a 5 and 138 b 5 associated with the screw head portions 138 a and138 b, respectively.

The plate 112 comprises a plurality of detents or lips 160, 162, 164 and166 (FIG. 15) that are integral with the walls 122-128, respectively.The plurality of detents or lips 160, 162, 164 and 166 cooperate withthe plurality of walls 122-128, respectively, to define the undercuts,channels or receiving areas 122 a-128 a. For ease of illustration, theoperation and function of one of the undercuts, channels or receivingareas 122 a-128 a, namely, the screw head undercut, channel or receivingarea 122 a and associated detent or lip 160 and screw 130, will now bedescribed.

In general and as illustrated in FIGS. 16A-16C and 17A-170, the tool 144is mounted in or received in the screw head 134 by inserting the maleworking surface 144 b of the tool 144 into the female working opening143. As the male working surface 144 b is aligned with the femaleworking opening 143, as illustrated in FIG. 17A, the tool 144 is guidedor driven axially into the screw head 134 until the curved, chamfer,beveled or angled surface 144 c of the male working surface 144 bengages at least a portion of the curved, chamfer, beveled or angledsurfaces 137 and 139 of the first and second head portions 138 a, 138 bas illustrated in FIGS. 178 and 22. As the male working surface 144 b isdriven further into the female working opening 143, the male workingsurface 144 b and the curved, chamfer, beveled or angled surfaces 137and 139 cooperate to urge the screw head portions 138 a and 138 b closertogether as shown in FIGS. 16A-16C, 178-170 and 22-23. Note in FIGS. 170and 23, when the male working surface 144 b is at least partially in thefemale member openings or apertures 140 and 142, and generally after thecurved, chamfer, beveled or angled surfaces 144 c of has cleared thecurved, chamfer, beveled or angled surfaces 137 and 139, the screw headportions 138 a and 138 b are fully compressed or urged together and mayengage as shown in FIGS. 170 and 23, which reduces an overall dimensionor diameter of the screw head 134 so that it can be inserted into theaperture 114 (FIG. 18A), for example, and past the detent or lip 160.Once the screw 130 is mounted onto the tool 144, the screw 130 and tool144 can be driven axially or moved into the aperture 114 as illustratedin FIG. 18A. Note that the screw head 134 has an expanded oruncompressed width or screw head diameter dimension 0104 (FIG. 17A) whenin the home position and a compressed or reduced dimension 0105 (FIG.170) when in the compressed position. The wall or channel 122 comprisesa diameter which is larger than the receiving aperture 114 dimension ordiameter 0107 defined by the inner surface 160 a of the detent or lip160. Note, however, that the dimension 0104 (FIG. 17A), which is thedimension of the first and second head portions 138 a and 138 b in anuncompressed state, is larger than the dimension 0109 (FIG. 18A) of theexit area 114 a defined by wall 156, but is slightly smaller than thedimension 0106, associated with the diameter of the wall 122. Incontrast, the compressed dimension 0105 (FIG. 170) is smaller than boththe dimensions 0106 and 0107. This permits the screw head 134 to bereceived in the aperture 114 and clear the detent or lip 160 when thescrew head portions 138 a and 138 b are compressed together asillustrated in FIGS. 170 and 18A, yet be retained by the detent or lip160 when the tool 144 is removed from the screw head 134 and the screwhead portions 138 a and 138 b are in the non-compressed or expandedstate illustrated in FIGS. 17A and 188.

Thus, the male working surface 144 b of the tool 144 is mounted in thefemale working opening 143 defined by the female member openings orapertures 140 and 142 to compress the screw head 134 by moving or urgingthe screw head portions 138 a and 138 b toward each other and toward theaxis A1 (FIG. 17A) of the screw 130. The compressed dimension 0105,illustrated in FIGS. 170 and 18A, is slightly smaller than the receivingopening dimension 0107 (FIG. 18A) so that as the tool 144 is rotated,the screw head 134 clears the detent or lip 160 as the screw 130 becomesscrewed into bone. The screw 130 is screwed into bone until theshoulders or surfaces 138 a 6 and 138 b 6 clear or move past a surface160 a of the internal detent or lip 160 in a manner similar to theembodiment described earlier herein relative to FIGS. 1-14. When thetool 144 is removed from the screw head 134, the first and secondelongated portions 136 a and 136 b and the screw head portions 138 a and138 b of the screw head 134 resiliently or elastically expand to thedecompressed home position illustrated in FIG. 188, whereupon thesurfaces 138 a 6 and 138 b 6 become generally opposed to the surface 160b of the internal detent or lip 160 as illustrated in FIG. 188. Notethat when this occurs, the surfaces 138 a 6 and 138 b 6 cooperate withthat surface 160 b and lip 160 to retain and lock the screw 130 in theplate 112 and prevent the screw 130 from withdrawing, for example, in anaxial direction away from bone (i.e., to the right as viewed in FIG.188).

Note in FIG. 188 that the diameter or dimension of the screw 130 in theelastic or resilient elongated portions 136 a and 136 b define an areaof flexion. As with the first embodiment, the dimension of this area offlexion may be slightly smaller in diameter or cross-section than thediameter or dimension of the threaded portion or shank 132. Thisfacilitates preventing external bone from engaging and/or compressingthe resilient elongated portions 136 a and 136 b which could interferewith the elastic or resilient expansion of the resilient elongatedportions 136 a and 136 b after the tool 144 has been removed from thescrew head 134 as illustrated in FIG. 188.

Again, the surfaces 138 a 6 and 138 b 6 clear the detent or lip 160before the screw 130 bottoms out in the seat or area 159. The bottomsurfaces 138 a 5 and 138 b 5 engage the seat or wall 159, therebypreventing the screw 130 from further travel. The surgeon then releasesthe tool 144 and the screw 130 re-expands or decompresses as described.

Note that in this embodiment, the screw 130 comprises the concavity area170 (FIGS. 17A-17D) that defines the generally opposing first and secondelongated portions 136 a and 136 b and the screw head portions 138 a and138 b as shown. As mentioned earlier, the inner walls 138 a 1 and 138 b1 that define the female member openings or apertures 140 and 142 areadapted, sized and shaped and cooperate to provide the female workingopening 143 for receiving the male working surface 144 b of the tool 144so that as the tool 144 is inserted in the female working opening 143,the screw head portions 138 a and 138 b become compressed together asillustrated in FIGS. 16A-16C and 178-170. The inner walls 138 a 1 and138 b 1 define the generally opposing female member openings orapertures 140 and 142 that are in fluid communication and open towardeach other as illustrated in FIGS. 17A-17D. In the illustration beingdescribed, the apertures have the same shape, but it should beunderstood that they could comprise different shapes is desired. Animportant feature of the inner walls 138 a 1 and 138 b 1 is that theydefine the camming surfaces 138 a 2, 138 a 3 and 138 b 2, 138 b 3 (FIGS.17A-17D), respectively. Note that as illustrated in FIG. 20, that themale working surface 144 b of the tool 144 has a common or similar shapein cross-section and is roughly the same size as the female workingopening 143 when the first and second head portions 138 a and 138 b arein the closed or compressed position illustrated in FIG. 170. Note thatas the male working surface 144 b is inserted progressively axially intothe female working opening 143, the first and second screw head portions138 a and 138 b are driven toward each other. To perform thiscompression or driving movement, note that the male working surface 144b comprises a plurality of camming surfaces 144 b 1, 144 b 2, 144 b 3and 144 b 4 that engage the camming surfaces 138 b 2, 138 b 3, 138 a 2and 138 a 3, respectively, as illustrated in FIGS. 22-23. As the maleworking surface 144 b is driven into the female working opening 143, thecamming surfaces 144 b 1 and 144 b 2 cam and engage the camming surfaces138 a 2 and 138 a 3, respectively, while the camming surfaces 144 b 3and 144 b 4 cam and engage the camming surfaces 138 b 2 and 138 b 3,respectively, along with the angled, beveled or chamfer surface 144 cand curved, chamfer, beveled or angled surfaces 137 and 139 and urge thescrew head portions 138 a and 138 b together until they reach a fullycompressed position illustrated in FIGS. 16C, 170 and 18A.

As mentioned earlier, to facilitate insertion of the male workingsurface 144 b into the female working opening 143, the tool 144 has theangled, beveled or chamfer surface 144 c (FIG. 19) that engages thesimilarly shaped curved, chamfer, beveled or angled surfaces 137 and 139(FIG. 17A), which facilitates guiding the male working surface 144 binto the female working opening 143. The curved, chamfer, beveled orangled surfaces 137, 139 and 144 c, also cooperate to guide the variouscamming surfaces with the surfaces 144 b 1, 144 b 2, 144 b 3 and 144 b4, respectively, into engagement with the camming surfaces 138 a 2, 138a 3, 138 b 2 and 138 b 3, respectively. In one embodiment, by the timethe angled, beveled or chamfer surface 144 c has passed the curved,chamfer, beveled or angled surfaces 137 and 139, the first and secondhead portions 138 a and 138 b are in the compressed state, asillustrated in FIGS. 16C and 170. Thus, it should be appreciated thatthe female working opening 143 is adapted and shaped by the inner walls138 a 1 and 138 b 1 which are generally mirror images of each other inthe illustration being described and which cooperate to provide themeans and camming surfaces that are adapted to cooperate with thecamming surfaces 144 b 1-144 b 4 to cause the first and second headportions 138 a and 138 b to be driven or urged together when the maleworking surface 144 b of the tool 144 is inserted into the femaleworking opening 143.

It should be appreciated that the female member openings or apertures140 and 142, which are defined by the inner walls 138 a 1 and 138 b 1are shown as being substantially the same shape and size, but it shouldbe appreciated that they could comprise other shapes and configurationsand that they do not have to be generally the same so long as theyprovide means and apparatus, such as the camming surfaces 138 a 2, 138 a3, 138 b 2 and 138 b 3 for driving the first and second head portions138 a and 138 b together upon insertion of the male working surface 144b of the tool 144. Of course, if the female working opening 143 changesin size, shape or configuration, the generally complementary-shaped maleworking surface 144 b would also be adapted, sized and shaped tocomplement the shape of the female working opening 143.

The concavity or separating area 170 illustrated in FIG. 17A, forexample, comprises one separating area that defines the first and secondpair of elongated portions 136 a and 136 b, but it should be appreciatedthat more separating areas could be provided so that additionalelongated members (not shown) are provided. For example, theconfiguration of the elongated members could be similar to that shown inthe embodiments of FIGS. 11-14 which define more than two elongatedmembers. Of course, each of the head portions (not shown) of thoseelongated members would have an internal or inner wall (not shown) thatdefines an aperture and camming surfaces that would be used with acomplementary shaped tool such that when the working surface of the toolis inserted into the apertures, it urges the screw head portionstogether in the manner described herein.

As mentioned earlier herein relative to FIG. 6, the embodiment shown inFIG. 18A provides the detent or lip 160 that provides a continuousundercut or receiving area 122 a about the aperture 114. It should beunderstood that while the detent or lip 160 in the embodiment describedrelative to FIG. 18A defines a continuous annular or radial surface 160b surrounding the aperture 114, this detent or lip 160 could also bediscontinuous to provide at least one or a plurality of detents thatcooperate with one or more of the surfaces 138 a 6 and 138 b 6 tofurther lock the screw 130 in the plate 112.

Advantageously, one additional benefit to the embodiments beingdescribed herein is a reduction in the number of steps required toremove the screw 130 from the plate 112. In this regard, thedisengagement of the locking of the screw 130 in the plate 112 occurswhen the tool 144 is inserted into the screw head 134 as describedherein and the bone screw 130 is unscrewed from the bone. As mentionedearlier, many prior art systems require multiple tools, for example, onetool to release the screw lock and another tool to screw or unscrew thescrew.

Another advantageous feature of the embodiment described herein is thatthe male projection, such as the male projections 40 and 42 in theembodiment described relative to FIGS. 1-14, are eliminated and a femaleaperture or female working opening 143 is provided. Also, the femaleworking opening 46 of the first embodiment is also eliminated. Replacingthe male projections 40 and 42 with the female working opening 143 ofthe first embodiment facilitates providing a more compact design withless protrusions from the screw head 134 or extending from the plate112.

This invention, including all embodiments shown and described herein,could be used alone or together and/or in combination with one or moreof the features covered by one or more of the claims set forth herein,including but not limited to one or more of the features or stepsmentioned in the Summary of the Invention and the claims.

While the system, apparatus and method herein described, and the form ofapparatus for carrying this method into effect, constitute preferredembodiments of this invention, it is to be understood that the inventionis not limited to this precise method and form of apparatus, and thatchanges may be made in either without departing from the scope of theinvention, which is defined in the appended claims.

1. An implant system comprising: at least one screw having: a screw bodyhaving a longitudinal slot or aperture along an axis of said screw bodyto define a plurality of resilient members; each of said plurality ofresilient members comprising an internal wall defining a flexible memberaperture, at least a portion of said internal wall defining a cammingsurface; said flexible member aperture of said plurality of resilientmembers cooperating to define a tool insertion aperture having apredetermined aperture shape; a tool having a working surface having apredetermined tool shape in cross section that generally complementssaid predetermined tool aperture shape; said working surface of saidtool engaging said camming surface and causing said plurality ofresilient members to assume a compressed position.
 2. A plate systemcomprising: a plurality of screws, each of said plurality of screwshaving a shank and a screw head; a plate having a plurality of aperturesfor receiving said plurality of screws, respectively, said plate furthercomprising a plurality of detents associated with said plurality ofapertures, respectively; at least a portion of said screw head beingadapted to be compressible when said at least one of said plurality ofscrews are screwed into bone and expandable so that it can be receivedin at least one of a plurality of screw head receiving areas; said atleast a portion of said screw head cooperating with at least one of saidplurality of detents to restrict or prevent said at least one of saidplurality of screws are from withdrawing from said plate.
 3. The platesystem as recited in claim 2 wherein said plate system further comprisesa tool having a working surface for compressing said at least a portionof said screw head after said at least a portion of said screw headreceives said working surface.
 4. The plate system as recited in claim 3wherein at least a portion of said screw head of each of said pluralityof screws comprises a plurality of resilient portions having receivingareas that cooperate to define a female opening for receiving saidworking surface.
 5. The plate system as recited in claim 4 wherein saidplurality of resilient portions each comprise an inner wall that definessaid receiving areas that have a camming surface, respectively, saidcamming surface being engaged by at least a portion of said workingsurface of said tool when said tool is inserted into said femaleopening.
 6. The plate system as recited in claim 2 wherein said platesystem further comprises a tool having a working surface, said at leasta portion of said screw head comprising a plurality of resilientportions each comprising an inner wall, at least a portion of said innerwall defines a camming surface that is adapted to be engaged by saidworking surface of said tool to drive said plurality of resilientportions together to a compressed position when said tool is insertedinto said screw head, said compressed position enabling said screw headto clear said at least one of said plurality of detents when said screwis inserted into said plate.
 7. The plate system as recited in claim 3wherein each of said plurality of screws comprise a plurality ofresilient portions, each of which are elastic or resilient and have aninner wall that defines a projection opening, said projection openingsof said plurality of resilient portions cooperate to define a femaleopening for receiving said working surface, at least a portion of saidinner wall defining a camming surface that is adapted to be engaged bysaid working surface of said tool when said tool is driven axially intosaid female opening until said plurality of resilient portions are in acompressed position, said compressed position being dimensioned suchthat said screw head clears said at least one of said plurality ofdetents when said screw is inserted into said plate.
 8. The plate systemas recited in claim 7 wherein each of said inner walls are generallyU-shaped in cross-section.
 9. The plate system as recited in claim 7wherein said working surface of said tool comprises a beveled or curvedsurface for engaging said camming surface and for causing said pluralityof resilient portions to assume said compressed position.
 10. The platesystem as recited in claim 9 wherein each of said inner walls comprisesa curved or beveled surface adapted to facilitate introducing saidworking surface of said tool into said female opening and for engagingsaid camming surface.
 11. The plate system as recited in claim 7 whereinsaid working surface of said tool comprises a beveled or curved surfacefor engaging said camming surface and each of said inner walls comprisesa curved or beveled surface adapted to facilitate introducing andguiding said working surface of said tool into engagement with saidcamming surface.
 12. The plate system as recited in claim 7 wherein saidplurality of resilient portions are normally in an unbiased orundeflected home position when said tool is not inserted into said screwhead so that after said screw head clears said at least one of saidplurality of detents and said tool is removed from said female opening,said plurality of resilient portions return to said unbiased orundeflected home position, whereupon at least a portion of at least oneof said plurality of resilient portions becomes operatively associatedwith at least one of said plurality of detents, thereby locking saidscrew in said plate.
 13. The plate system as recited in claim 6 whereineach of said camming surfaces extends generally radially inwardly towardan axis of said screw.
 14. The plate system as recited in claim 6wherein said inner wall is non-circular and comprises at least oneraised or inwardly-projecting projection surface that defines saidcamming surface.
 15. The plate system as recited in claim 5 wherein whensaid plurality of resilient portions are driven toward each other andinto a compressed position, said screw head clears said at least one ofsaid plurality of detents when said screw is inserted into said plate.16. The plate system as recited in claim 3 wherein said screw headcomprises a plurality of screw head portions each having a femaleopening, said female opening cooperating to define a female workingopening for receiving a tool such that when said tool is inserted intosaid female working opening said plurality of screw head portions aredriven together to a compressed position.
 17. The plate system asrecited in claim 6 wherein said inner wall is not circular and definesor provides a plurality of inner walls in said plurality of resilientportions, respectively, said plurality of inner walls having a pluralityof camming surfaces, respectively, that may be engaged by a plurality ofworking portions of said working surface of said tool when said tool isinserted into a female working opening, thereby driving said pluralityof screw head portions together.
 18. The plate system as recited inclaim 17 wherein each of said plurality of inner walls is generallyU-shaped or Omega-shaped in cross section.
 19. The plate system asrecited in claim 16 wherein said female working opening defines apredetermined shape.
 20. The plate system as recited in claim 19 whereinsaid predetermined shape is a figure eight or bowtie shape.
 21. Theplate system as recited in claim 17 wherein said tool comprises apredetermined shape in cross section that is adapted to have engagingsurfaces for engaging said camming surfaces in order to drive saidplurality of screw head portions to said compressed position.
 22. Theplate system as recited in claim 21 wherein said tool predeterminedshape is a figure eight or bowtie shape in cross section.
 23. The platesystem as recited in claim 4 wherein said plurality of detents comprisea plurality of undercut walls, respectively, that define a plurality ofundercuts associated with said plurality of apertures, respectively,each of said plurality of undercut walls defining a receiving area forreceiving at least a portion of said plurality of resilient portions.24. The plate system as recited in claim 4 wherein each of saidplurality of detents defines a generally U-shaped wall that defines anundercut associated with each of said plurality of apertures, saidgenerally U-shaped wall defining a generally U-shaped receiving area forreceiving at least a portion of said plurality of resilient portions.25. The plate system as recited in claim 2 wherein said screw headcomprises a concaving or separating area that defines each of aplurality of elongated members, each of said plurality of elongatedmembers being resilient, elastic or movable so that they can be movedtoward each other in response to axial insertion of a working surface ofa tool into said screw head.
 26. The plate system as recited in claim 16wherein said plurality of screw head portions comprises inner walls thatcooperate to define a female working opening, said inner walls alsohaving at least one camming surface that engages and are driven by aworking surface of said tool to a compressed position when said workingsurface is inserted axially into said female working opening.
 27. Theplate system as recited in claim 26 wherein said plurality of screw headportions extend generally longitudinally and parallel to an axis of saidshank.
 28. The plate system as recited in claim 27 wherein saidplurality of screw head portions comprises a first portion thatgenerally opposes a second portion. 29-86. (canceled)